In 1980 , Americans spent 2 billion minute makinginternational sound Call . By 2004 , that material body jumped to 64 billion arcminute [ source : Federal Communications Commission ] . Why the vast increment ?
International song are meretricious than they were in 1980 . That makes it easier for foreign - born citizen to call the phratry back home . An increase in international business and travelling is also responsible . The most popular international call markets from the United States are Canada , Mexico , the United Kingdom , Germany and India . These countries account for 38 percent of all outside shout [ source : Federal Communications Commission ] .
The very first transatlantictelephonecable break operational in 1956 . It could only handle 36 calls at a time and cost $ 12 for the first three minutes ( the equivalent weight of $ 92 in 2007 ) . That ’s skilful than the very first transatlantic calls made via radio signals in 1927 . Those be $ 75 for the first three minutes ( $ 872 in today ’s money ! ) [ reference : AT&TandThe Inflation Calculator ] .
It ’s not loose to construct and asseverate a worldwide telephony internet . keep up with the increasing demand for international telephone set calls has need the cooperation and collaborative try of governments and private telecommunications companies around the orb . Organizations like theInternational Telecommunication Union(a United Nations agency ) help set the external numbering measure and technology protocols that safely route call across oceans and Continent .
How does the international enumeration scheme work ? How was it established ? And , why is it crucial ? Go to the next page to bump out .
The Public Switched Telephone Network
The Public Switched Telephone internet ( PSTN ) , also known asPlain Old Telephone Service ( POTS ) , is the pumped-up telephone system over which landlinetelephonecalls are made . The PSTN relies oncircuit switching . To connect one phone to another , the phone call is routed through legion switches operating on a local , regional , national or international level . The connection instal between the two telephone is ring acircuit .
In the early daytime , phone phone call travel as analog signal across atomic number 29 wire . Every phone call needed its own consecrate copper telegram connecting the two phones . That ’s why you needed hustler ' assist in making call . The operators sat at a switchboard , literally connecting one composition of copper wire to another so that the call could travel across town or across the country . Long - distance claim were comparatively expensive , because you were renting the use of a very longsighted small-arm of copper wire every sentence you made a call .
start in the 1960s , voice call began to be digitized and manual shift was put back by automatise electronic switching [ origin : WirelessCenter ] . Digital voice signals can partake in the same telegram with many other phone calls . The Parousia offiber - opticcables now allows thousand of calls to share the same line of products . But fibre - eye and other high - bandwidth cable have n’t changed the basic nature of circuit switching , which still postulate a connection – or circuit – to stay open for the distance of the speech sound call .
Routing calls require multiple switch over situation . The phone number itself is a twit map for gouge the call . In the United States , for example , we have 10 - digit speech sound turn .
Within a company or larger organization , each employee or section might have its ownextension . extension from the master phone telephone number are routed through something call aprivate branch exchange ( PBX)that operate on the premise .
To make an outside call requires further instructions . The call require to be rout through your long - aloofness headphone aircraft carrier to another body politic ’s long - distance phone flattop . To signal such a substitution , you have to dial two disjoined Book of Numbers , your country’sexit code(orinternational access computer code ) and the correspondingcountry codeof the place you ’re foretell .
Almost allexit codesare either 00 or 011 , although there are a few exceptions like Cuba ( 119 ) and Nigeria ( 009 ) . state code are one- to three - digit prefixes that are arrogate to specific countries or grouping of commonwealth . For instance , the res publica code for the United States is 1 , but the United States shares that country code with Canada and several smaller island Carry Nation like Jamaica , Puerto Rico and Guam . The country code for Mexico is 52 and Saudi Arabia is 966 . Here ’s afull inclination of exit and country codes .
Now let ’s find out who sets the standard by which the international telephone system operates .
The Telecommunication Standardization Sector
The Telecommunication Standardization Sector is part of the International Telecommunication Union ( ITU ) , an agency of the United Nations . The ITU , based in Geneva , Switzerland , works with 191 fellow member countries to develop and enforce global communication engineering science .
The specific duty of the Telecommunication Standardization Sector ( ITU - T ) is to search and urge standard and communications protocol relating to voice and data point infection over land line and mobile internet . This includes everything from streaming video on cell phone to Voice over IP ( VoIP ) to SMS to international call charge per unit .
When it was found in 1925 , the ITU - T was called the Comité Consultatif International Téléphonique et Télégraphique ( CCITT ) . The CCITT was responsible for for breakthrough study in standardise fax information transmissions , modem , data point compression , packet - switching and e - mail . The CCITT became the ITU - T in 1993 as part of a new strategic architectural plan to respond faster to the ever - alter technical landscape [ reference : International Telecommunication Union ] .
The ITU - T is best known for itsrecommendations . As their name incriminate , recommendations are n’t law or regulated standards , but just suggestions for the best way to make telecommunications technology and networks persist smoothly . Recommendations are established by 13study groupswithin the ITU - T. Each report group is comprised of external managers andrapporteurs(appointees ) from the public and private sector . A distinctive study group might admit a CTO from Israel , a researcher from Germany and an American policymaker from the Federal Communications Commission .
Study group are ascribe a handful ofquestions , which they research over the course of two to four long time before publish their recommendations . Questions resemble topics . Current examples of questions let in :
The ITU - T also organizesfocus groups , which are smaller research units within a study grouping working on a specific trouble or question . Recommendations are bring out online and are gratis to the public as well as secret diligence and government agencies .
Next let ’s utter about the ITU - T good word that found the current external enumeration programme .
The Numbering Plan E.164
TheE.164recommendation , also hollo the " international public telecommunications numbering program , " was first approved and published by the ITU - T in May 1997 . The E.164 recommendation establishes a standard framework for every country to create its own outside phone numbers .
An external E.164 figure is design to include all of the necessary information to successfully route a call to an individual ratifier on a nation ’s publictelephonenetwork . Here ’s how the E.164 enumeration architectural plan puzzle out :
The combined length of the national ( pregnant ) bit ca n’t top ( 15 - n ) , wherenis the amount of figure in the rural area code . This allow each area to decide how many fingerbreadth should be in the national destination code and the indorser number . A country with a relatively diminished population and few major metropolis , for example , might take to have fewer digit in their telephone numbers . And for larger countries , the possibilities are nearly sempiternal . A 15 - finger number countenance for 100 trillion different permutation , enough for each somebody on earthly concern to have 10,000 phone numbers [ source : SearchNetworking ] .
The E.164 recommendation is presently being enlarge into a much broader protocol called ENUM , short for TElephoneNUmberMapping . Using the international E.164 number as a mannikin , ENUM will assign a specific Uniform Resource Identifier ( URI ) to each and every networked gimmick , include analog telephone set and facsimile machine machines , mobile phones , computers and PDA . With this new URI , all these machine will be capable to contact each other directly using a undivided mesh computer address / phone number . As of this composition , a concluding ENUM passport has n’t been release .
For lots more data abouttelephonecountry codification and related to topics , check out the connectedness on the next page .
